package danLi;
public class Singleton {
        private Singleton(){};
        private static volatile Singleton instance;
        public static Singleton getInstance(){
            if(instance==null){
                synchronized (Singleton.class){
                    if (instance==null){
                        instance=new Singleton();
                    }
                }
            }
            return instance;
        }
    public static void main(String[] args) {
        System.out.println(getInstance());
        System.out.println(getInstance());

    }
}

